*{
    margin: 0;
    padding: 0;
}
.wrap{
    width: 600px;
    height: 600px;
    /* border: 1px solid; */
    margin: 50px auto;
    position: relative;
}
.wrap .smallBox{
    width: 200px;
    height: 200px;
    border: 1px solid red;
    position: absolute;
}
.wrap .smallBox img{
    width: 200px;
    height: 200px;
}
.wrap .smallBox span{
    width: 100px;
    height: 100px;
    position: absolute;
    width: 80px;
    height: 80px;
    background: rgba(200,200,200, 0.6);
    left: 0;
    top: 0;
    cursor: move;
    display: none;
}
.wrap .bigBox{
    width: 200px;
    height: 200px;
    border: 1px solid;
    position: absolute;
    left: 230px;
    top: 0;
    overflow: hidden;
    display: none;
}
.wrap .bigBox img{
    width: 400px;
    height: 400px;
    position: absolute;
}